From mboxrd@z Thu Jan 1 00:00:00 1970 From: Fenghua Yu Subject: [PATCH v6 08/20] x86/split_lock: Enumerate split lock detection on Icelake mobile processor Date: Wed, 3 Apr 2019 14:21:54 -0700 Message-ID: <1554326526-172295-9-git-send-email-fenghua.yu@intel.com> References: <1554326526-172295-1-git-send-email-fenghua.yu@intel.com> Cc: "linux-kernel" , "x86" , linux-wireless@vger.kernel.org, netdev@vger.kernel.org, kvm@vger.kernel.org, Fenghua Yu To: "Thomas Gleixner" , "Ingo Molnar" , "Borislav Petkov" , "H Peter Anvin" , "Dave Hansen" , "Paolo Bonzini" , "Ashok Raj" , "Peter Zijlstra" , "Kalle Valo" , "Xiaoyao Li " , "Michael Chan" , "Ravi V Shankar" Return-path: In-Reply-To: <1554326526-172295-1-git-send-email-fenghua.yu@intel.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org Icelake mobile processor can detect split lock operations although the processor doesn't have MSR_IA32_CORE_CAPABILITY and split lock detection bit in the MSR. Set split lock detection feature bit X86_FEATURE_SPLIT_LOCK_DETECT on the processor based on its family/model/stepping. A few other processors may also have the feature but don't have MSR_IA32_CORE_CAPABILITY. The feature will be enumerated on those processors once their family/model/stepping information is released. Signed-off-by: Fenghua Yu --- arch/x86/kernel/cpu/intel.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c index ad3f72d106fc..7f6943af35dc 100644 --- a/arch/x86/kernel/cpu/intel.c +++ b/arch/x86/kernel/cpu/intel.c @@ -1038,8 +1038,18 @@ void __init cpu_set_core_cap_bits(struct cpuinfo_x86 *c) { u64 ia32_core_cap = 0; - if (!cpu_has(c, X86_FEATURE_CORE_CAPABILITY)) + if (!cpu_has(c, X86_FEATURE_CORE_CAPABILITY)) { + /* + * The following processors have split lock detection feature. + * But since they don't have MSR_IA32_CORE_CAPABILITY, the + * feature cannot be enumerated by the MSR. So enumerate the + * feature by family/model/stepping. + */ + if (c->x86 == 6 && c->x86_model == INTEL_FAM6_ICELAKE_MOBILE) + set_split_lock_detect(); + return; + } /* * If MSR_IA32_CORE_CAPABILITY exists, enumerate features that are -- 2.19.1